共查询到20条相似文献，搜索用时 78 毫秒
1.
本文分别以单、双侧u检验为例。讨论了犯两类错误的概率α与β以及样本容量n之间的关系,同时给出了计算犯第二类错误的概率β的具体方法。最后以单侧u检验为例,导出了确定样本容量n的公式。 相似文献
2.
论述了指数分布族的一致最优检验是存在的,并给出一致最优检验及样本容量确定的方法步骤,求出了常见分布的一致最优检验. 相似文献
3.
文依据教育测量学、教育统计学理论，结合内蒙古自治区１９９８年高考试题分析，论证了确定合理抽取样本容量的依据和方法，对抽样结果进行了检验。结果表明：用此容量确定的样本统计量十分接近总体参数，具有较好的总体代表性 相似文献
4.
确定样本容量的一种方法 总被引：1，自引：0，他引：1
叶健 《江苏广播电视大学学报》1997,(2)
本文针对统计推断中确定样本容量这一问题，运用数理统计原理，推导出一种根据允许的最大误差确定样本客量的方法。 相似文献
5.
李鹏祥 《黄冈师范学院学报》2009,(Z1):119-120
在总体均值的区间估计中,样本容量对区间估计的精度有着重要影响。本文从理论上探讨了三种情况下总体均值区间估计精度的理论计算,并重点分析了样本容量对总体均值区间估计精度的影响原因,这对通过确定样本容量来控制估计精度以优化检测过程具有重要意义。 相似文献
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7.
本文研究了仿真试验可靠性估计的样本容量确定问题：当目标是矩形域时,给定置信水平1-α,如何确定样本容量,使得估计真实可靠度的误差在δ内。 相似文献
8.
比较试验(假设检验)作为统计推断的一种方法,在产品质量检验中发挥着重要作用。鉴于现有的假设检验大多局限于正态分布,因此进行了总体服从指数分布的比较试验设计。讨论了总体的参数估计与假设检验问题,并分别从单边和双边检验角度进行分析,根据实际问题需要,结合数值分析算法,利用C++语言编写出自动确定试验时所应抽取的样本容量及判断满足工程精度要求的拒绝域端点的程序。 相似文献
9.
二阶抽样下样本容量最优分配 总被引：2，自引：0，他引：2
样本容量的确定是抽样调查中的一个重要内容。本文根据精度与费用之间的关系。利用求多元函数条件极值的方法,确定当第一级抽样为有放回PPS抽样,第二级抽样为简单随机抽样时。二阶抽样的样本容量最优分配。 相似文献
10.
《中国考试》2019,(9)
随着多级计分在心理和教育领域中日益广泛的应用,对检验项目功能差异(DIF)的方法提出新的挑战。已有研究表明,在检验DIF的方法中,MIMIC是一种经济有效的检验方法,然而还没有研究系统地分析MIMIC方法在多级计分项目中的有效性。本研究通过蒙特卡洛实验,探讨参照组与目标组的样本容量、DIF类别、项目区分度、组间能力差异和在锚题中存在的DIF题量5个因素,并在这些因素不同情况的组合中分析MIMIC方法的第一类错误率和检验力。研究发现:1)MIMIC是一种能够灵敏地检验一致性DIF的方法,即使在目标组样本容量较小或明显小于参照组的情况下,它仍然能很好地控制第一类错误率;2)纯化步骤对MIMIC方法控制第一类错误率、提高检验力是有必要的,但MIMIC方法对污染程度又有一定的容忍性;3)检验力受到低区分度的严重影响,但太高的区分度又会导致第一类错误率的增加;4)MIMIC方法对一致性DIF的检验力随着样本容量的增大而增大。 相似文献
11.
产品焊接试板是压力容器生产工艺控制的重要环节，产品质量是否可靠，焊接试板检测结果是主要的判据。本文分析了薄焊接试较弯曲试样失效的原因，并对减少失效的可能性作出了阐述。 相似文献
12.
以工程实际为依托,根据击实试验结果在实际工程中的应用深入浅出的将土工击实试验的理论基础、作用机理做了详细的描述;对试验主要使用仪器、试验所用土样的制样、击实过程及试验数据处理步骤进行了说明;并对可能会影响试验结果的因素进行了归纳和总结。 相似文献
13.
Sadie Goldsmith 《Journal of Experimental Education》2013,81(4):343-345
Type I error rate and power for the t test, Wilcoxon-Mann-Whitney (U) test, van der Waerden Normal Scores (NS) test, and Welch-Aspin-Satterthwaite (W) test were compared for two independent random samples drawn from nonnormal distributions. Data with varying degrees of skewness (S) and kurtosis (K) were generated using Fleishman's (1978) power function. Five sample size combinations were used with both equal and unequal variances. For nonnormal data with equal variances, the power of the U test exceeded the power of the t test regardless of sample size. When the sample sizes were equal but the variances were unequal, the t test proved to be the most powerful test. When variances and sample sizes were unequal, the W test became the test of choice because it was the only test that maintained its nominal Type I error rate. 相似文献
14.
This article describes an interactive activity that involves students participating in a memory recall test. Data collected from the activity may be used to illustrate the one‐sample t test or one‐sample sign test. 相似文献
15.
Donald W. Zimmerman 《Journal of Experimental Education》2013,81(3):171-174
A computer program generated power functions of the Student t test and Mann-Whitney U test under violation of the parametric assumption of homogeneity of variance for equal and unequal sample sizes. In addition to depression and elevation of nominal significance levels of the t test observed by Hsu and by Scheffé, the entire power functions of both the t test and the U test were depressed or elevated. When the smaller sample was associated with a smaller variance, the U test was more powerful in detecting differences over the entire range of possible differences between population means. When sample sizes were equal, or when the smaller sample had the larger variance, the t test was more powerful over this entire range. These results show that replacement of the t test by a nonparametric alternative under violation of homogeneity of variance does not necessarily maximize correct decisions. 相似文献
16.
Four pigeons served as subjects in an experiment using the go/no-go delayed matching-to-sample paradigm. The go/no-go method was used because it permits the experimenter to track the time course of discriminative performance throughout the test period, unlike the conventional choice matching procedure. It was found that discriminative test performance increased with longer sample durations; performance decreased with longer retention intervals and also as time passed in the test period. The rate of forgetting was virtually the same when either the retention interval was lengthened or time elapsed in the test. These findings support a modified trace theory, which proposes that the sample stimulus trace decays at a constant rate from the point of sample offset, and that the decaying memory trace is repeatedly compared with the prevailing test stimulus as time passes in the test period. 相似文献
17.
Educational measurement specialists in undertaking test equating in applied settings have been plagued by the absence of a logically or mathematically compelling rationale for their test equating efforts. Classical test theory and other test theories based on the assumption of identically distributed true scores are tautological in terms of test equating. The present study examined (by means of a Monte Carlo procedure) the effects of four parameters on the accuracy of test equating under a relaxed definition of test form equivalence. The four parameters studied were sample size, test form length, test form reliability, and the correlation between the true scores of the test forms to be equated. Significant interactions involving sample size and the other parameters indicated that smaller samples of observations yielded disproportionately larger errors in test equating for fixed values of the test form parameters. In terms of main effects, sample size emerged as most important in controlling equating error. Taken together, the results suggest that when test equating is carried out on larger samples of observations, errors of equating will tend to be relatively small even though the test forms are not strictly parallel. For arbitrarily small samples, however, errors of equating will tend to be larger regardless of how equivalent the test forms are. 相似文献
18.
The absolute normal scores test (K) is described as a test for the symmetry of a distribution of scores about a location parameter designated as 0. The test is compared to the sign test (S) and the Wilcoxon test (W) as an alternative to the t-test. Power comparisons are made among the K, S, W, and t tests. An example is presented where the sample size is less than 20. The large sample approximation to the normal distribution is also illustrated. 相似文献
19.
王存嫦 《衡阳师范学院学报》1993,(6)
本文介绍了在燃烧热的测定实验中采用双孔带槽模底,单、双股燃烧丝相结合的挂样片法,代替单孔或无孔模底,单股燃烧丝接触样片法,以及压片操作技法。四年的实践表明,这种实验方法大大提高了实验的成功率,缩短了实验操作时间。 相似文献